首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1524篇
  免费   116篇
  国内免费   6篇
耳鼻咽喉   26篇
儿科学   40篇
妇产科学   96篇
基础医学   245篇
口腔科学   125篇
临床医学   135篇
内科学   249篇
皮肤病学   48篇
神经病学   160篇
特种医学   30篇
外科学   125篇
综合类   4篇
预防医学   154篇
眼科学   13篇
药学   70篇
肿瘤学   126篇
  2024年   1篇
  2023年   8篇
  2022年   13篇
  2021年   16篇
  2020年   21篇
  2019年   25篇
  2018年   41篇
  2017年   30篇
  2016年   37篇
  2015年   39篇
  2014年   43篇
  2013年   54篇
  2012年   112篇
  2011年   105篇
  2010年   56篇
  2009年   50篇
  2008年   105篇
  2007年   95篇
  2006年   90篇
  2005年   87篇
  2004年   85篇
  2003年   78篇
  2002年   63篇
  2001年   36篇
  2000年   37篇
  1999年   19篇
  1998年   9篇
  1997年   11篇
  1996年   12篇
  1995年   8篇
  1994年   12篇
  1993年   10篇
  1992年   40篇
  1991年   19篇
  1990年   20篇
  1989年   20篇
  1988年   15篇
  1987年   15篇
  1986年   18篇
  1985年   17篇
  1984年   19篇
  1983年   8篇
  1982年   5篇
  1981年   6篇
  1980年   10篇
  1979年   16篇
  1978年   7篇
  1977年   3篇
排序方式: 共有1646条查询结果,搜索用时 15 毫秒
81.
There is increasing evidence that healthy siblings of schizophrenia patients have similar, although milder, neuropsychological deficits than their affected family members. However, the interpretation of these findings has been complicated by methodological differences, for example the selection of relatives studied and the sensitivity of tests used. We studied neuropsychological functioning in schizophrenia families in representative, population-based samples of schizophrenia patients (n=81) and healthy siblings (n=78) from 58 families, and control subjects (n=70). We found that the healthy sibling group was impaired in tests measuring performance speed and executive functions. The patients were significantly impaired in all neuropsychological variables studied when compared with the control subjects, and also when compared with the healthy siblings. The effects of age, sex and education were controlled for. In conclusion, in a study of representative, population-based sample the healthy siblings of schizophrenia patients demonstrated deficits in processing speed and executive functions.  相似文献   
82.
BACKGROUND: There are few reports on mobility limitations in persons with psychotic disorder although restrictions in mobility may aggravate the general functional limitations of these patients. Our aim was to investigate mobility limitations among subjects with psychotic disorder in a general population-based sample. METHODS: A nationally representative sample of 6,927 persons aged 30 and older self-reported mobility limitations in an interview and was examined in performance tests. Diagnostic assessment of DSM-IV psychotic disorders combined SCID interview and case note data. Lifetime-ever diagnoses of psychotic disorder were classified into schizophrenia, other nonaffective psychotic disorders and affective psychoses. RESULTS: Self-reported mobility limitations were highly prevalent in persons with schizophrenia and other nonaffective psychosis, but not in the affective psychosis group. After adjusting for age and sex, persons with schizophrenia and other nonaffective psychoses but not affective psychoses had significantly increased odds of having both self-reported and test-based mobility limitations as well as weak muscle strength. Schizophrenia remained an independent predictor of mobility limitations even after controlling for lifestyle-related factors and chronic medical conditions. Among persons with nonaffective psychoses, higher levels of negative symptoms predicted mobility limitations. CONCLUSION: Self-reported mobility limitations are prevalent already at a young age in persons with schizophrenia and other nonaffective psychotic disorders, and among older persons with these disorders both self-reported limitations and measured performance tests show lower capacity in mobility. Difficulties in mobility are associated with negative symptoms. Mental health care professionals should pay attention to mobility limitations in persons with psychotic disorder.  相似文献   
83.
BACKGROUND: The changes in the activity of a number of plasma markers of coagulation and fibrinolysis have previously been studied in patients with ischemic stroke, with conflicting results. We aimed to find out the changes in the activities of a wide array of markers of the coagulation and the fibrinolytic system of mildly or moderately affected first-ever ischemic stroke patients. METHODS: In a prospective, longitudinal, case-control study, we studied plasma plasminogen activator inhibitor type-1 (PAI-1) activity, tissue-type plasminogen activator antigen (t-PA:Ag), d-dimer, prothrombin fragment 1+2 (F 1+2), and thrombin-antithrombin III complex (TAT) levels in 55 consecutive patients on admission, 1 week, 1 month, and 3 months after an ischemic stroke. Sex- and age-matched controls were studied once. All patients underwent blood sampling at each study time point; comprehensive stroke risk factors were recorded, and the etiology of the ischemic stroke was determined. All patients were contacted 3 years later for possible recurrent ischemic events. RESULTS: PAI-1 activity was increased in the acute phase and at 3 months, D-dimer levels were significantly higher at 1 week and 1 month after stroke, whereas t-PA:Ag, TAT and F 1+2 levels remained stable during the whole study period. CONCLUSIONS: The changes of the fibrinolytic and coagulation system activity in the patients with mild or moderate ischemic stroke appeared minor compared with the results of previous studies, which included more severely ill patients.  相似文献   
84.
Aims   To investigate whether substance use disorders (SUDs) are associated with verbal intellectual ability, psychomotor processing speed, verbal and visual working memory, executive function and verbal learning in young adults, and to study the associations of SUD characteristics with cognitive performance.
Participants   A population-based sample ( n  = 466) of young Finnish adults aged 21–35 years.
Measurements   Diagnostic assessment was based on all available information from a structured psychiatric interview (SCID-I) and in- and out-patient medical records. Established neuropsychological tests were used in the cognitive assessment. Confounding factors included in the analyses were comorbid psychiatric disorders and risk factors for SUDs, representing behavioural and affective factors, parental factors, early initiation of substance use and education-related factors.
Findings   Adjusted for age and gender, life-time DSM-IV SUD was associated with poorer verbal intellectual ability, as measured with the Wechsler Adult Intelligence Scale–Revised (WAIS-R) vocabulary subtest, and slower psychomotor processing, as measured with the WAIS-R digit symbol subtest. Poorer verbal intellectual ability was accounted for by parental and own low basic education, whereas the association with slower psychomotor processing remained after adjustment for SUD risk factors. Poorer verbal intellectual ability was related to substance abuse rather than dependence. Other SUD characteristics were not associated with cognition.
Conclusions   Poorer verbal intellectual ability and less efficient psychomotor processing are associated with life-time alcohol and other substance use disorders in young adulthood. Poorer verbal intellectual ability seems to be related to parental and own low basic education, whereas slower psychomotor processing is associated with SUD independently of risk factors.  相似文献   
85.
86.
Purpose: The Pyhäjärvi Cataract Study aims to study demand for cataract surgery in the population of a rural town in Finland. Methods: A random, population‐based sample of 881 persons aged ≥ 60 years were interviewed by telephone to obtain a Visual Function‐14 (VF‐14) score. A total of 294 persons were invited for an ophthalmic examination based on three categories of VF‐14 score. Of these, 230 (78%) responded, 10 of whom were excluded as a result of prior bilateral surgery. The New Zealand Priority Criteria (NZPC) and the 15‐Dimension Quality of Life (15‐D) instruments were administered. In addition, another group of 96 patients waiting for cataract surgery were examined and scored using the VF‐14, NZPC and 15‐D instruments. A modified Lens Opacities Classification System (LOCS) III classification was used for grading the cataract. Results: Only one (0.5%) of the 220 examined subjects was referred for cataract surgery. Many patients with relatively good visual acuity (VA), including six people with a 100‐point VF‐14 score suggesting no visual symptoms, were waiting for surgery. Demographic factors were not associated with access to cataract surgery. The patients examined from the waiting list for cataract surgery had more cataractous changes in the lens(es), poorer VA, were older, and scored higher on the NZPC instrument than the population sample examined. Conclusions: Practically no hidden demand for cataract surgery was found in the study population as defined by the national criteria for cataract surgery in Finland. This reflects the fact that the current Finnish health care system appears to recognize and treat cataract patients very well, even in rural areas. Although VA tests may not be sufficient for evaluating need for cataract surgery, the role of questionnaires is not clear either.  相似文献   
87.
88.
Recently, Epstein-Barr virus (EBV) has gained increasing attention as a potential causative agent of Sj?gren's syndrome, which is an autoimmune disorder characterized by lymphocytic infiltration of salivary and lacrimal glands. To determine the association between Sj?gren's syndrome and EBV, we re-evaluated the salivary gland biopsies from patients previously diagnosed to have Sj?gren's syndrome. Altogether, 20 cases of Sj?gren's syndrome were reviewed from the files of the University Central Hospital since 1975. After re-evaluation of these biopsies, however, 11 patients did not fulfil the current criteria of Sj?gren's syndrome, but were diagnosed as having chronic sialadenitis. All biopsies were processed for in situ hybridization (ISH) and polymerase chain reaction (PCR) to detect EBV DNA. With ISH, all samples were negative for EBV DNA. With PCR, however, 9 biopsies proved to be positive for EBV. 3 additional positive cases were found when the amplification product was dot-blotted and hybridized with EBV DNA probe. 10 of the EBV-positive salivary gland biopsies showed the histological features of chronic sialadenitis and only 2 cases were classified as having Sj?gren's syndrome. On the basis of the present results, the association between EBV and Sj?gren's syndrome remains doubtful.  相似文献   
89.
Bronchial changes in airborne tularemia   总被引:1,自引:0,他引:1  
We describe seven typhoidal tularemia patients without ulcers or lymphadenopathy, who underwent diagnostic bronchoscopy. Four patients had had obvious airborne exposure to F. tularensis during farming activities, and the remaining three had respiratory symptoms also. Bronchoscopical findings were pathological in all cases, varying from local to diffuse haemorrhagic inflammation; in one case a granulomatous tumour was seen. Early histopathological changes in three biopsies consisted of haemorrhagic oedema progressing to a non-specific inflammatory reaction, which could still be found 45 days after the onset of symptoms. Granulomatous inflammation, indistinguishable from tuberculosis or sarcoidosis, was seen in four biopsies from two patients, three to seven months after the onset. Most patients had radiographic hilar enlargement. We conclude that transmission of typhoid tularemia usually occurs through inhalation leading to bronchial changes, which correspond skin ulcerations in ulcero-glandular tularemia, the hilar enlargement corresponding to the lymph node component. We emphasize that usage of the term 'typhoidal' tularemia should be discontinued. Instead, tularemia transmitted through inhalation should be called pulmonary or respiratory.  相似文献   
90.
A total of 513 women with cervical HPV infections have been followed-up since 1981 (mean 25.6 months) to establish the biological potential of HPV in cervical carcinogenesis. On each attendance, the patients were subjected to colposcopy accompanied by Papanicolaou (PAP) smears and/or punch biopsies. The latter were analysed for HPV particles on TEM, for the cytopathic changes of HPV, as well as for HPV structural proteins. The local immunocompetent cell (ICC) infiltrates are enumerated using ANAE-technique to define B-, MPS- and T cells, and monoclonal antibodies for T cell subsets, NK and K cells and Langerhans cells. HPV DNA typing was accomplished by Southern blot and spot hybridization using the DNA probes for HPV 6, 11, 16 and 18. Antibody titres for HSV were measured, and Chlamydia trachomatis isolations completed in cervical swabs. No correlation with the clinical course, e.g. regression (RE), persistence (PE), progression (PR) or recurrence (RC) of the HPV lesions could be established for the following factors; expression of HPV antigens, presence of HPV particles on TEM, Chlamydia in cervical swabs, the levels of HSV antibodies, and the levels of the ICCs. The OKT4+/OKT8+ cell ratio, however, was inversely correlated with PR, being most markedly reduced in recurrent lesions. Of the 513 lesions, 24.8% regressed, 59.8% remained persistent, and 14.1% progressed, 11.9% having been coned due to progression into CIS. So far, 1.1% of lesions have recurred after such a treatment. The progression rate was highest (45.5%) in HPV 16 lesions, followed by that (27.3%) in HPV 18 lesions, as contrasted to 0% and 13.3% for HPV 6 and 11, respectively. The results clearly confirm that cervical HPV infections are capable of progressing into CIS and thus show a natural history equivalent to that of classical CIN. The inherent potential of HPV 16 and HPV 18 lesions for clinical progression was clearly established, supporting the concept on HPV 16 and HPV 18 as the high risk HPV types in cervical carcinogenesis.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号